Last and first frost dates in Fort Collins

When is the last frost in Fort Collins?

The last frost in Fort Collins usually comes around 25 April: that is the median of 2016–2025, so in about half of those years the last night at or below 0 °C came later. Hardy crops start before it and frost-tender ones only after it: in the table below arugula can go into open ground from 4 April, while corn waits until 2 May. The first autumn frost follows around 21 October, about 179 days later: harvest or cover frost-tender crops before then.

When to sow and plant

Planting out: a week after the last frost once the soil is warm enough for the crop; frost-hardy crops three weeks before it; an unheated greenhouse three weeks earlier. Seedlings are sown so they are ready on that day. Each window starts on the Greenly calendar date and ends on the last day that still leaves the crop’s days to harvest (from its card) before the average first autumn frost, plus six weeks of picking for crops harvested over weeks (tomatoes, peppers, aubergines, cucumbers, courgettes, pumpkins, watermelons, beans) — our rule; earlier in the window is safer.

When the soil warms up in Fort Collins

The day the top 7 cm of soil first averages each temperature over a week, median of 2016–2025 (ERA5 via Open-Meteo). The soil reaches 10 °C 14 days before the last spring frost and 15 °C 19 days after it.

Frost dates near Fort Collins

Of the nearest cities on our list, the last spring frost ends earliest in Pueblo (21 April) and latest in Casper (26 May).

Seeds, seedlings and markets in Fort Collins

Within 15 km of Fort Collins OpenStreetMap lists 10 garden centres, 4 farm-supply shops, 2 plant nurseries, 3 markets and 6 farm shops (collected 28 October 2026). The nearest garden centre to the city centre is Bath Garden Center and Nursery, 3 km away.

• Bath Garden Center and Nursery — garden centre
  East Prospect Road 2000, 80525 Fort Collins · Mon–Fri 08:00–19:00; Sat 08:00–18:00; Sun 09:00–17:00 · 3 km · bathgardencenter.com
• Poudre Pet & Feed Supply — farm supply
  North College Avenue 622 · 5 km · poudrefeed.com
• Drake Road Farmers Market — market
  West Drake Road 802, Fort Collins · Jun–Oct Sat 10:00–13:00 · 2 km · drakeroadfarmersmarket.com
• Green Dog Farms — farm shop
  West Vine Drive 1807, Fort Collins · 6 km
• Horsetooth Stem and Roots — garden centre
  Mon–Sat 11:00–18:00; Sun 11:00–17:00 · 4 km
• Poudre Pet & Feed Supply — farm supply
  South College Avenue 6204, 80525 Fort Collins · Mon–Fri 07:30–19:00; Sat 07:30–17:00; Sun 10:00–17:00 · 6 km · naturalfeedstore.com

• Where to buy seeds and seedlings in Fort Collins
• Selling your own harvest in the United States

Places: © OpenStreetMap contributors, ODbL.

Weather in Fort Collins by month

Average weather in Fort Collins over 2016–2025: the warmest month is July. Months that average 20 °C or more by day: May–September (21.1–31.6 °C). Months that average 30 °C or more by day: July (31.6 °C) and August (30.5 °C). Nights average below 0 °C in November–March (-8.2–-1.7 °C). About 404 mm of rain falls in a year, on 73 days; May is the wettest month (95 mm) and December the driest (14 mm).

Average of the daily highs and lows, rain per month and days with at least 1 mm (ERA5 via Open-Meteo, the same grid cell as the frost dates).

Planted in autumn

From a month before the first autumn frost, so the roots grow before winter, to the late-planting limit on each crop’s page (about two weeks before the ground freezes, by ten years of weather).